The source is autogenerated. I've attached the relevant file. The entire project is available at https://github.com/riscv/riscv-debug-spec/tree/release. If I had to make a minimal case it would look as follows, but I don't know how to make the alignment happen in a way to show the problem outside of the document itself:\usepackage{enumitem}\newenvironment{steps}[1] { \vspace{1ex} \noindent #1 \begin{enumerate}[nolistsep] } { \end{enumerate} \vspace{1ex} }

\subsubsection{Quick Access}\begin{steps}{Perform the following sequence of operations:} \item If the hart is halted, the command sets \Fcmderr to ``halt/resume'' and does not continue. \item Halt the hart. If the hart halts for some other reason (e.g. breakpoint), the command sets \Fcmderr to ``halt/resume'' and does not continue.... \end{steps}

Perhaps post the .log file here, as attachment. A warning in that file could point to the issue. Or post a a compilable version of the document, as attachment, even if it's not small. Downloading from github and figuring out how to compile etc. took too much time for me for now so a test was not possible.

I've made the whole thing one big .tex file and cut out most of the unnecessary bits.

I've attached the .tex file, .log, console log, and the final pdf. You can see the problem on the page break between the penultimate and last pages of the pdf, where item number 1 is missing from the list.

I'm a pretty basic LaTeX user. Usually it does something reasonable, but in this case I have no idea how to even begin to troubleshoot this problem.

Replacing nolistsep with noitemsep does fix the problem, but I don't want that. I want no separation between lines in the steps environment, but of course I never ever want anything rendered off the end of the page. Is there some other way to achieve that while still allowing page breaks where they should be?

Another thing that looks funny to me is how low on the page the subsubsection{Quick Access} starts. It already appears to be below the usual drawable area of the page. Could there be something about center/longtable that's causing trouble?